Metallurgical process



UNITED STATES PATENT OFFICE.

JOHN TYLER JONES, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 THOMAS J.

HOWELLS, OI IITTSBURGH, PENNSYLVANIA.

METALLURGICAL PROCESS- No Drawing.

To all whom it may concem:

Be it known that I, JOHN TYLER JONES, a citizen of the United States,and a resident of Pittsbur h, in the county of Allegheny and State 0Pennsylvania, have invented a new and useful Improvement inMetallurgical Processes, of which the following is a specification.

My invention relates to improvements in metallurgical processes, moreparticularly 1 those processes which relate to the reduction of ores andthe production of metal in the form of the pure elements such as iron,aluminum, etc., or the production of alloys such as ferroman'ganese, andit consists in the steps hereinafter described.

An object of my invention is to provide a process by means of whichmetals may be economically reduced from the1r ores.

A further object of my invention is to provide a process which can becarried out quickly, thereby resulting in a saving of time as well as incost.

A further object of my invention is to provide a process for reducingores which does not require the use of specially designed machiner tocarry out the process, but which may e carried out through the use ofordinary apparatus such as a regenerative coking oven and a regenerativefurnace.

Other objects and advantages will appear in the following specification,and the novel features of the invention will be particularly pointed outin the appended claims.

In various parts of the countries are lar e deposits of relatively lowgrade ore. 11 many instances the ore is of such low grade that it hasnot up to the present time been profitably handled. Man of thesedeposits are in what is known as lanket formation, that is to say, theore is found just beneath the top soil at distances approximating twentyfeet (20), and is substantiall level with the surface of the groundinstea of being inclined in veins. Other veins occur which are inclined.As an instance of a blanket formation, I may cite the depositofmanganese ore in the Cuyuna range in Minnesota. Iron ore will occur inveins and there are large deposits of bauxite from which aluminum may beobtained at a relatively low cost.

The present process may besuccessfully carried out or used in connectionwith the Specification of Letters Patent.

Patented May 24, 1921.

Application iiled October 26, 1917. Serial No. 198,674.

recovery of a variety of metals such as iron, alum1num,-silicon, etc. Aspecific instance W111 suffice to show the manner in which the process1s carried out. Let us take the case of aluminum. Hitherto it has beennecessary to subject the aluminum ore to a high heat 1n an electricfurnace in order to effect the reduction. In carrying out the invent1on,the bauxite is first crushed in any suitable crushing device, to afineness approximating from twenty to one hundred mesh. Crushedbituminous coal of a fineness substantially equivalent to that of theore is intimately mixed with the bauxite. Instead of coal, any otherhydrocarbon havin volatile matter capable of bein driven 0 under heatand of being ignited for furnishing the heat with which the ore isreduced, may be used instead of the coal. Any such material is reducedto a state of fineness correspondmg with that of the ore. In mixing thecrushed ore and hydrocarbon, any suitable mixer may be used, such as arotating barrel or the like. It is necessary that an excess of the coalor hydrocarbon bearing element'be used, and to this end, I make use of amixture of one-third of ore and substantially two-thirds of coal or itsequivalent hydrocarbon bearing material, although these proportions maybe varied without de- .partmg from the spirit of the invention.

The mixed material is put into a furnace or retort and heated. Theparticular form of retort does not constitute a part of the presentinvention. An ordinary Siemens regenerative coking oven or an ordinaryby-product oven may be used and the temperature at which the mixture isheated is preferably the highest'temperature ordinarily used in makingcoke.

he material, that is to say, the mixed coaland ore, or the mixedhydrocarbon bearing material and ore, is left in the oven long enough tothoroughly coke the mass. The time depends, of course, upon the size ofthe oven. In the case of bituminous coal, some ovens require twenty-fourhours while others require forty-eight, and others perhaps, seventy-two.When the mixed ore and coal is ut in a small crucible and heated themass is coked in a few minutes.

Assuming that coal has been used, after the material has been coked itis taken out of the oven in a red-hot condition and water is turned onit as in the ordinary process of making coke. The product is a substancewhich has very much the appearance of coke. ()n close examination,however, it will be found that the metal is in a metallic state, that isto say, instead of being in the ox d form, it is in the metal form andthe end has been substantially driven off. In the case of aluminum, thealuminum has been deoxidized at the temperature at which coal isordinarily coked. This temperature is greatly below that required in thereduction of the metal in an electric furnace. The precise reasons forsuch action are not definitely known. It may be that the nascent gasessuch as hydrogen which are more active in their nascent state, have agreater affinity for the oxygen than such gases would have when they arenot in the nascent state. In any event, I have found that the metalexists in the coked mass in the metallic form and is scatteredthroughout the mass, the particles of aluminum apparently beingseparated by particles of coke.

The product is now in a state from which the aluminum can be readilyremoved. This is done by placing the coked mass in an ordinary meltingfurnace such as an open hearth, a blast furnace, or any ordinary form ofmelting furnace, In the case of aluminum, the coal or rather the coke,is burned away, the metal melts and may be collected in any suitableform. In a co-pending application I have described a process ofproducing ferromanganese, in which iron oxid and manganese oxid arereduced to the metallic form, so that the coked product is a mixture ofiron and manganese in the metallic form separated by particles of coke.In such a product, I may separate the iron by crushing the mass and thentreating it magnetically. The manganese may be subsequently separated,and the coke is recovered as such. Right here, I desire to callattention to the fact that approximately as much coke is recovered aswould be produced by the same amount of coal. In other words, it is notthe coke itself which is consumed to deoxi- (llZG the metals, but it isthe volatile constituents of the coke which produce the reduction. Thisin itself is a very important economical advance in the art, since inroducing ferromanganese, the coked pro uct may be separated into itsmetallic elements and the remaining coke may be sold. Furthermore, whena by-product oven is used not only are the volatile portions of the coalused in bringing the metals to the metallic state, but certainconstituents of the excess of volatile matter may be recovered inaddition. This again renders the process still more economical.

In the case of aluminum, the reduction in the cost of producing themetal is such that the burning away of the coke plays a very small part.

The process described herein, it will be noted, requires that the ore bein a finely divided state. It is also necessary that the hydrocarbonbearing material such as coal, be in a correspondingly divided state.The Whole tendency of modern metallurgy, at least up to the time ofapplicants invention, has been to get away from the finely dividedstate, that is to say, to carry out the operation with lumps of ore, notsmall particles of ore or ore dust. The reason is obvious; in theordinary operation, dust is blown out of the furnaces. Whole sectionsaround metal reduction works are covered with this fine dust and,therefore, the tendency has been to exert every effort to keep down thedust, because not only does it form a nui-' sance in the surroundingcommunity, but it causes an actual loss of material. In my process .Imake use of every bit of the crushed material. The crushed material isput into an air-tight heating device, no dust can possibly escape, thefiner the material, the better is the coked product, and the quicker thereduction takes place. The coked product is an agglomerated mass whichmay be handled without inconvenience and which is in the state fromwhich the metal may be easily obtained as described.

The agglomerated mass or coked product has very much the appearance ofordinary coke, but on microscopical examination, it is found to consistof articles of metal separated by particles of coke. The material itselfis novel, as far as applicant is aware, and the bringing of the metalinto the pig form is very readily accomplished.

In carrying out my process it will be observed that the mixed ore andhydrocarbon bearing material isaccomplished substantially out of thepresence of air. As a matter of fact, only enough air is admitted toinsure the combustion of a sufficient quantity of the coal to coke theremaining mass, substantially as in the ordinarycoking operation, whenthe air is shut off.

In the final melting of the metal as, for instance aluminum, into thepig, air is admitted so as to provide for the combustion of the cokeduring the melting step.

I claim:

1. The herein described process of treating metalliferous ores, whichconsists in crushing the ore to a fineness approximating twenty to onehundred mesh, mixing with the crushed ore an excess of crushed coalhaving substantially the same fineness, heating the mixed ore and coaltogether, substantially out of the presence of air, to a temperaturesufficient to coke the coal and to produce an agglomerated massresembling coke, and subsequently separating the metals from the coke.

2. The herein described process of treating metalliferous orescontaining a metal heating the mixture to a coking temperature oxid,which consists in crushing the ore to to form an agglomerated coke masscona fineness approximating twenty to one huntaining the metals inmetallic form and 10 dred mesh, mixing said crushed ore with coke, andsubsequently separating the metals 5 hydrocarbon bearing material of afineness from the coke.

approximating that of the ore, said hydrocarbon bearing material beingin excess, JOHN TYLER JONES.

